Interpretive Summary: Development of safe and effective alternative methods is becoming a priority for poultry industry due to increasing concerns about increasing drug-resistance of poultry pathogens. Although drugs have been traditionally used to control many diseases of poultry, the results of recent ARS study indicate a potential non-drug application of dietary strategy to control mucosal pathogens of poultry. In this report, ARS scientists in collaboration with scientists at Pancosma, S.A., in Switzerland demonstrated novel immunomodulation strategies to enhance gut innate immunity in poultry using plant phytonutrients. Extracts of turmeric or shiitake mushroom killed chicken tumor cells and enhanced the production of chicken cytokines including IL-1ß, IL-6, IL-12, IL-18, and TNFSF15 in vitro. These results document the immunologically-based enhancement of innate immunity in chickens by extracts of plants and mushrooms with known medicinal properties in vitro. This information will be used to develop an in vivo model of immunomodulation strategy to enhance innate immunity of broiler birds using a dietary method.

Technical Abstract:
The present study was conducted to examine the effects of milk thistle (Silybum marianum), turmeric (Curcuma longa), reishi mushroom (Ganoderma lucidum), and shiitake mushroom (Lentinus edodes) on innate immunity and tumor cell viability. In vitro culture of chicken spleen lymphocytes with extracts of milk thistle, turmeric, and shiitake and reishi mushrooms induced significantly higher cell proliferation compared with the untreated control cells. Stimulation of macrophages with extracts of milk thistle and shiitake and reishi mushrooms, but not turmeric, resulted in robust nitric oxide production to levels that were similar with those induced by recombinant chicken interferon-'. All extracts uniformly inhibited the growth of chicken tumor cells in vitro at the concentration of 6.3 through 100ug/ml. Finally, the levels of mRNAs encoding IL-1ß, IL-6, IL-12, IL-18, and TNFSF15 were enhanced in macrophages that were treated with extracts of turmeric or shiitake mushroom compared with the untreated control. These results document the immunologically-based enhancement of innate immunity in chickens by extracts of plants and mushrooms with known medicinal properties in vitro. In vivo studies are being planned to delineate the cellular and molecular mechanisms responsible for their mechanism of action.